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Re: [ccp4bb]: Re: [o-info] Centralized binaries



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On Wednesday 24 April 2002 13:19, Robert Campbell wrote:
>
> In response to Christopher A. Waddling who wrote about centralizing
> OSX binaries:
>
> * Gordon Webster <gordon_webster@hms.harvard.edu> [2002-04-24 14:13] 
wrote:
> > This is a good idea and it certainly works as long as your network
> > is healthy ...
> >
> > The downside of this arrangement is that if your network crashes or
> > suffers gridlock, nobody can do any work at all (been there, done
> > that). In addition, there can be a considerable time overhead in
> > loading large binaries over a network and you need to be very
> > careful how you set up things like shareable libraries, scratch
> > files and working directories, so that this network overhead does
> > not also cause your applications to continue dragging their heels
> > once they are launched.
>
> I don't recall hearing complaints about the slowness of loading large
> binaries over the network (more likely to be about loading
> diffraction images over the network! -- of course one of the local
> users that follows this list is liable to complain later today or
> tomorrow :) ). 

Exactly.  In a distributed computing environment the transfer of data
is far more likely to be a bottleneck than the time it takes to load an
executable from an NFS-mounted disk.  If it's a frequently used 
executable then it may well be cached in local memory anyhow.

There is one thing to avoid if at all possible, however.
LD_LIBRARY_PATH should never include NFS-mounted directories, because
if it does and the NFS server goes incommunicado even briefly then
essentially nothing you try to execute from the command line will 
work.  The shell will hang trying to search that unavailable
directory even if you are trying to run something that could not
possibly care about it. So even if your application programs live in a 
central location, the shared libraries they rely on should either 
reside on local disk or be bound explictly to the executable image (how 
to do this varies with OS).

-- 
Ethan A Merritt       merritt@u.washington.edu
Biomolecular Structure Center Box 357742
University of Washington, Seattle, WA 98195
phone: (206)543-1421
FAX:   (206)685-7002